How to make Flappy Bird Game in Pygame?

Last Updated : 31 Aug, 2021

In this article, we are going to see how to make a flappy bird game in Pygame.

We all are familiar with this game. In this game, the main objective of the player is to gain the maximum points by defending the bird from hurdles. Here, we will build our own Flappy Bird game using Python.

We will be using Pygame(a Python library) to create this Flappy Bird game. Pygame is an open-source library that is designed for making video games. it helps us to create fully functional games and multimedia programs in python.

First of all, You have to install the Pygame library using the command:-

pip install pygame

Stepwise Implementation

Step 1: In this first step, we have to import libraries.

After that, we have to set the height and width of the screen to which the game will be played. Now we have to define some images which we shall use in our game like pipes as hurdles, birds images, and also a background image of the flappy bird game.

Python3

# For generating random height of pipes import random   import sys  import pygame from pygame.locals import *   # Global Variables for the game window_width = 600 window_height = 499  # set height and width of window window = pygame.display.set_mode((window_width, window_height))    elevation = window_height * 0.8 game_images = {}       framepersecond = 32 pipeimage = 'images/pipe.png' background_image = 'images/background.jpg' birdplayer_image = '/images/bird.png' sealevel_image = '/images/base.jfif'

Step 2: After declaring game variables and importing libraries we have to initialize the Pygame

The used file can be downloaded from here.

Initialize the program using pygame.init() and set the caption of the window. Here pygame.time.Clock() will be used further in the main loop of the game to alter the speed the bird. Load the images from the system in pygame using pygame.image.load().

Python3

# program where the game starts if __name__ == "__main__":                    # For initializing modules of pygame library     pygame.init()       framepersecond_clock = pygame.time.Clock()          # Sets the title on top of game window     pygame.display.set_caption('Flappy Bird Game')            # Load all the images which we will use in the game     # images for displaying score     game_images['scoreimages'] = (         pygame.image.load('images/0.png').convert_alpha(),         pygame.image.load('images/1.png').convert_alpha(),         pygame.image.load('images/2.png').convert_alpha(),         pygame.image.load('images/3.png').convert_alpha(),         pygame.image.load('images/4.png').convert_alpha(),                 pygame.image.load('images/5.png').convert_alpha(),         pygame.image.load('images/6.png').convert_alpha(),         pygame.image.load('images/7.png').convert_alpha(),         pygame.image.load('images/8.png').convert_alpha(),         pygame.image.load('images/9.png').convert_alpha()     )     game_images['flappybird'] = pygame.image.load(birdplayer_image).convert_alpha()                       game_images['sea_level'] = pygame.image.load(sealevel_image).convert_alpha()     game_images['background'] = pygame.image.load(background_image).convert_alpha()     game_images['pipeimage'] = (pygame.transform.rotate(pygame.image.load(pipeimage)                                                         .convert_alpha(),                                                         180),                                 pygame.image.load(pipeimage).convert_alpha())      print("WELCOME TO THE FLAPPY BIRD GAME")     print("Press space or enter to start the game")

Step 3: Initialize the position of the bird and starting the game loop

Initialize the position of bird and sea level to the ground. Adding conditions in the loop defines the game conditions. The variable horizontal and vertical is used to set the position of the bird. We have to run the program until the user stops or exits (using sys.exit())if the program so, we create an infinite while loop.

Python3

while True:          # sets the coordinates of flappy bird         horizontal = int(window_width/5)         vertical = int((window_height - game_images['flappybird'].get_height())/2)                  # for selevel         ground = 0           while True:             for event in pygame.event.get():                  # if user clicks on cross button, close the game                 if event.type == QUIT or (event.type == KEYDOWN and event.key == K_ESCAPE):                     pygame.quit()                                          # Exit the program                     sys.exit()                     # If the user presses space or up key,                 # start the game for them                 elif event.type == KEYDOWN and (event.key == K_SPACE or event.key == K_UP):                     flappygame()                                  # if user doesn't press anykey Nothing happen                 else:                     window.blit(game_images['background'], (0, 0))                     window.blit(game_images['flappybird'], (horizontal, vertical))                     window.blit(game_images['sea_level'], (ground, elevation))                                          # Just Refresh the screen                     pygame.display.update()                                                  # set the rate of frame per second                     framepersecond_clock.tick(framepersecond)

Step 4: Create a function that generates a new pipe of random height

First of all, we have to fetch the height of the pipe using getheight() function. After this generates a random number between 0 to a number (such that the height of the pipe should be adjustable to our window height). After that, we create a list of dictionaries that contains coordinates of upper and lower pipes and return it.

Python3

def createPipe():     offset = window_height/3     pipeHeight = game_images['pipeimage'][0].get_height()          # generating random height of pipes     y2 = offset + random.randrange(       0, int(window_height - game_images['sea_level'].get_height() - 1.2 * offset))       pipeX = window_width + 10     y1 = pipeHeight - y2 + offset     pipe = [                # upper Pipe         {'x': pipeX, 'y': -y1},                  # lower Pipe         {'x': pipeX, 'y': y2}       ]     return pipe

Step 5: Now we create a GameOver() function which represents whether the bird has hit the pipes or fall into the sea.

According to my thought, three conditions lead to a situation of the game over. if the difference between our elevation and a certain height is less than vertical it means the bird has crossed its boundaries resulting in a game over and if the bird hits any of the lower and upper pip then this will also lead to game over condition.

Python3

# Checking if bird is above the sealevel. def isGameOver(horizontal, vertical, up_pipes, down_pipes):     if vertical > elevation - 25 or vertical < 0:          return True      # Checking if bird hits the upper pipe or not     for pipe in up_pipes:             pipeHeight = game_images['pipeimage'][0].get_height()         if(vertical < pipeHeight + pipe['y']             and abs(horizontal - pipe['x']) < game_images['pipeimage'][0].get_width()):             return True                # Checking if bird hits the lower pipe or not     for pipe in down_pipes:         if (vertical + game_images['flappybird'].get_height() > pipe['y'])          and abs(horizontal - pipe['x']) < game_images['pipeimage'][0].get_width():             return True     return False

Step 6: Now we will be creating our main function (flappygame()) that will do the following things:

Initialize the variables and creating two pipes by createPipe() function. Create two lists first is of lower pipes and the other is of lower pipes. Defining the bird velocity, minimum bird velocity, maximum bird velocity, and pipes velocity. Handle the key events using pygame.event.get() and checking for the game is over or not if it is over return from the function. Updating the score and blit game images such as background, pipe, and bird on the window.

Python3

def flappygame():     your_score = 0     horizontal = int(window_width/5)     vertical = int(window_width/2)     ground = 0     mytempheight = 100      # Generating two pipes for blitting on window     first_pipe = createPipe()     second_pipe = createPipe()      # List containing lower pipes     down_pipes = [         {'x': window_width+300-mytempheight,          'y': first_pipe[1]['y']},         {'x': window_width+300-mytempheight+(window_width/2),          'y': second_pipe[1]['y']},     ]      # List Containing upper pipes      up_pipes = [         {'x': window_width+300-mytempheight,          'y': first_pipe[0]['y']},         {'x': window_width+200-mytempheight+(window_width/2),          'y': second_pipe[0]['y']},     ]      pipeVelX = -4 #pipe velocity along x      bird_velocity_y = -9  # bird velocity     bird_Max_Vel_Y = 10        bird_Min_Vel_Y = -8     birdAccY = 1           # velocity while flapping     bird_flap_velocity = -8          # It is true only when the bird is flapping     bird_flapped = False       while True:                 # Handling the key pressing events         for event in pygame.event.get():             if event.type == QUIT or (event.type == KEYDOWN and event.key == K_ESCAPE):                 pygame.quit()                 sys.exit()             if event.type == KEYDOWN and (event.key == K_SPACE or event.key == K_UP):                 if vertical > 0:                     bird_velocity_y = bird_flap_velocity                     bird_flapped = True          # This function will return true if the flappybird is crashed         game_over = isGameOver(horizontal, vertical, up_pipes, down_pipes)         if game_over:             return          # check for your_score         playerMidPos = horizontal + game_images['flappybird'].get_width()/2         for pipe in up_pipes:             pipeMidPos = pipe['x'] + game_images['pipeimage'][0].get_width()/2             if pipeMidPos <= playerMidPos < pipeMidPos + 4:                   # Printing the score                 your_score += 1                 print(f"Your your_score is {your_score}")          if bird_velocity_y < bird_Max_Vel_Y and not bird_flapped:             bird_velocity_y += birdAccY          if bird_flapped:             bird_flapped = False         playerHeight = game_images['flappybird'].get_height()         vertical = vertical + min(bird_velocity_y, elevation - vertical - playerHeight)          # move pipes to the left         for upperPipe, lowerPipe in zip(up_pipes, down_pipes):             upperPipe['x'] += pipeVelX             lowerPipe['x'] += pipeVelX          # Add a new pipe when the first is about         # to cross the leftmost part of the screen         if 0 < up_pipes[0]['x'] < 5:             newpipe = createPipe()             up_pipes.append(newpipe[0])             down_pipes.append(newpipe[1])          # if the pipe is out of the screen, remove it         if up_pipes[0]['x'] < -game_images['pipeimage'][0].get_width():             up_pipes.pop(0)             down_pipes.pop(0)          # Lets blit our game images now         window.blit(game_images['background'], (0, 0))         for upperPipe, lowerPipe in zip(up_pipes, down_pipes):             window.blit(game_images['pipeimage'][0],                         (upperPipe['x'], upperPipe['y']))             window.blit(game_images['pipeimage'][1],                         (lowerPipe['x'], lowerPipe['y']))          window.blit(game_images['sea_level'], (ground, elevation))         window.blit(game_images['flappybird'], (horizontal, vertical))                  # Fetching the digits of score.         numbers = [int(x) for x in list(str(your_score))]         width = 0                  # finding the width of score images from numbers.         for num in numbers:             width += game_images['scoreimages'][num].get_width()         Xoffset = (window_width - width)/1.1                  # Blitting the images on the window.         for num in numbers:             window.blit(game_images['scoreimages'][num], (Xoffset, window_width*0.02))             Xoffset += game_images['scoreimages'][num].get_width()                      # Refreshing the game window and displaying the score.         pygame.display.update()                  # Set the framepersecond         framepersecond_clock.tick(framepersecond)

Below is the full implementation :